Eucharist is the name that Catholic Christians give to the sacrament by which, according to their belief, the body and blood of Christ are present in the bread and wine consecrated during the Catholic eucharistic liturgy, generally known as the Mass. The definition of the Eucharist in the 1983 Code of Canon Law as the sacrament where Christ himself "is contained, offered, and received" points to the three aspects of the Eucharist according to Catholic theology: the real presence of Christ in the Eucharist, Holy Communion, and the holy sacrifice of the Mass.

The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.39 billion baptized Catholics worldwide as of 2022. It is among the world's oldest and largest international institutions, and has played a prominent role in the history and development of Western civilization. The church consists of 24 sui iuris churches, including the Latin Church and 23 Eastern Catholic Churches, which comprise almost 3,500 dioceses and eparchies located around the world. The pope, who is the bishop of Rome, is the chief pastor of the church. The Diocese of Rome, known as the Holy See, is the central governing authority of the church. The administrative body of the Holy See, the Roman Curia, has its principal offices in Vatican City, a small independent city-state and enclave within the Italian capital city of Rome, of which the pope is head of state.